Today's IT infrastructures are composed of a large number of heterogeneous, distributed stateful IT resources (see also layer “IT Resources” in FIG. 1). That is, IT services typically comprise or are hosted by several heterogeneous IT resources (e.g. servers, operating systems on those servers, databases, application server software, etc.). We use the term IT Service Environment for a collection of resources and a set of behavioral conditions that all together define a specific IT service. IT services may be part of outsourcing agreements of IT services providers with customers, or they may be in-house applications.
For each of the resources used by IT Services several resource-specific management functions are available for controlling the operation of a resource, i.e. for creating (provisioning), destroying (de-provisioning) and controlling the operation and configuration of a stateful resource. Resource management functions of a resource may also control other resources—for example, a resource that acts as a resource manager may offer a service to create/provision a new instance of a certain other resource. The described view on the management capabilities of resources is depicted as “Systems Management Layer” in FIG. 1. This layer summarizes the management interfaces of the resources.
In order to perform systems management in the scope of a whole IT Service Environment (in contrast to single resources) an integration of single Systems Management Tasks into a systems-wide Systems Management Flow is necessary in order to treat the IT Service Environment as a whole and to keep it in a consistent state (see also layer “Systems Management Flows” in FIG. 1). Thus Systems Management Flows play a key role for the management of IT Services.
As an example for a Systems Management Flow, let us assume that a new server WebServer3 has to be provisioned as depicted in FIG. 2. The related simplified Systems Management Flow could contain following Tasks (the following list first mentions the resources that perform the Tasks followed by a brief description of the Tasks):
Cluster1: task install and start image: get a new server from the server free pool and name it WebServer3; load and install a system image that contains an operating system and a web server application on WebServer3 from an image management system; reboot WebServer3; add a relationship from Cluster1 to WebServer3
WebServer3: task initial application start: register at name server; start web server application
LoadBalancer: task register web server: add host name and IP-address of WebServer3 to the list of available web servers for load balancing
There are various techniques available for implementing Systems Management Flows as described in chapter “Prior Art”.